As computers and computer networks become more and more able to access a wide variety of information, people are demanding more ways to obtain that information. Specifically, people now expect to have access, on the road, in the home, or in the office, to information previously available only from a permanently connected personal computer hooked to an appropriately provisioned network. They want stock quotes and weather reports from their cell phones, e-mail from their personal digital assistants (PDAs), up-to-date documents from their palm tops, and timely, accurate search results from all their devices. They also want all of this information when traveling, whether locally, domestically, or internationally, in an easy-to-use, portable device.
Portability generally requires a device small in size, which in turn limits the number of data entry keys and the amount of memory and available processing power. In addition, ultra portable devices often must be held in one hand or not held at all, so that data entry must be one-handed or no-handed. These limitations in the device generally must be compensated for by the user. For example, the user may have to use a limited keyboard such as a telephone keypad, or limited speech recognition capabilities. Such constrained devices may force a user to learn special tricks for data entry (such as shorthand writing on a PDA) or may generate data that the user never intended, by making inaccurate guesses at ambiguous data entries.
Some attempts to solve these problems have been made. For example, PDAs have been programmed to recognize shorthand and longhand writing. However, the recognition accuracy may be poor, and writing on a small mobile device may be difficult for users. Also, cell phones can recognize entered letters, even though the presence of three letters on each key can create ambiguities about the intended text, such as by allowing the user to press key combinations, either simultaneously or in sequence (e.g., triple tap). However, methods that include pressing key combinations, such as triple tap, may require a user to generate substantially more keystrokes than if the user had access to a keyboard. The increase in keystrokes may slow down a user's interaction with the device and discourage retrieving and entering information using mobile devices.